White truffle: £222 per gram
In 2010, the most expensive Alba white truffle ever sold, weighing 1.3kg, went to Macau billionaire Stanley Ho for $417,200, meaning he paid $320.92 per gram.
However, presumably less superior Alba white truffles can be bought for around £3 per gram.
#4 & #7... Not sure what I am missing here.. But it seems that if I grind my solid gold bars up into a fine powder I can increase it's value by 700%.. from $28 to $200 a gram??